Professors envision giant solar energy farm atop concrete channel.

Flood control and land development were the objectives more than four decades ago when a 10.5-mile stretch of the Tijuana River was transformed into a broad concrete channel. Now two San Diego professors have a different dream: using the channel to produce solar energy and to treat runoff and wastewater.

René Peralta and Jim Bliesner envision a giant energy farm along the length of the channel that would consist of solar panels across the top. Down below, they propose using algae systems to clean the water that flows down the river and eventually ends up in the Pacific Ocean. Interspersed along the channel would be trees, a parkway, and opportunities for art and vendors.

The plan grew out of a class taught by Bliesner and Peralta at University of California San Diego, where both have been lecturers in the urban studies department. The idea was to look at ways to improve the quality of life through urban design.

“We thought this could roll over into Mexico,” Peralta said. “We had this huge canal that had all these issues, that wasn’t doing much when it didn’t rain. We thought this could be an interesting issue.”

Peralta concedes that it “began as pie in the sky,” but said the proposal addresses very real issues — such as the need to find uses for the large quantities of water that run down the channel and end up being discharged into the Pacific Ocean.

The project “is going to be very hard to get jump-started,” said Rick Van Schoik, portfolio director of the North American Research Partnership, a nonprofit network of analysts who look at ways the United States, Mexico and Canada can collaborate. “But everyone always complains there is no vision. These guys brought a vision.”

Peralta directs the master of science program in architecture, landscape and urbanism at Woodbury University in San Diego, while Bliesner heads the nonprofit Center for Urban Economics and Design that collaborates with Woodbury and UC San Diego.

They’ve presented the project to the North American Development Bank, as well as at last month’s environmental conference put on by the Tijuana Innovadora civic group, called Green Tijuana-San Diego Verde.

At a recent private presentation in downtown San Diego, with members of several nonprofit groups in the audience, Peralta said the project’s energy production capacity would be about 94 megawatts — enough to power 30,000 homes or a 112-acre industrial park.

Before even seeking financial support, they would need permission from Mexico’s federal government to move forward. Like all rivers in Mexico, the channel is under federal control, and any plans would have to be approved by Mexico’s National Water Commission.

The proposal comes amid growing opposition to concrete channels such as the Tijuana River, “because they are not good for the environment … they stop percolation of water into the aquifer, they interrupt natural functioning of the systems,” said Paul Ganster, a professor at San Diego State University and director of the school’s Institute for Regional Studies of the Californias. “Tijuana needs more green areas, it doesn’t need more industrial uses of urban land, and that’s what solar farms would be.”

To the north, Los Angeles has been moving toward restoring its concrete river channel, with plans that include a $453 million project to restore some 600 acres of wildlife habitat.

Peralta said Tijuana doesn’t have access to that kind of funding, and his proposal is more in keeping with the city’s reality.

Tijuana “does not have the luxury of reinventing the river to what it once was,” and the solution lies in “hybridizing its old infrastructure with new technologies,” Peralta said.

Today, the Tijuana River channel carries a steady and narrow stream in its center of about 13 million gallons daily, most of it treated wastewater from Tijuana and Tecate, that is discharged into the ocean.

Over the years, the concrete channel has been the setting for a number of other activities besides flood control, including the occasional concert venue and the canvas for some colorful giant murals.

Tijuana officials earlier this year evacuated a stretch near the U.S. border that had become a center for hundreds of homeless people and drug addicts, many of them deportees. An effort known as Bordofarms to create small urban gardens on its banks for deportees also ended this year when the federal government said they could not stay.

Peralta and Bliesner say their concept is in very initial phases, with much work yet to be done. “We need to dig three feet deeper into the details of the project,” Bliesner said. But their hope is to create a project that would find funding through North American Development Bank, or through California’s cap-and-trade program that uses market mechanisms to support projects that lower greenhouse gas emissions.

“This could be a private-public venture, where a company might be interested in doing the solar panels investment and sell the power to the CFE,” Mexico’s Federal Electricity Commission, Peralta said.

Decades ago, before the channelization project was launched in July 1972, this area was known as Cartolandia, a flood-prone area whose low-income residents lived in shacks made up of scrap materials. The channeling gave birth to Tijuana’s Zona Río with its government offices, restaurants, Plaza Río shopping mall and Tijuana’s Cultural Center.

Peralta said the energy project would not eliminate the channel’s flood control function, simply enhance its uses.

“That’s the spirit of Tijuana, it’s always reinventing and and repurposing things,” said Peralta. “That’s why this project on a larger scale symbolizes that.”